Extremely Loud and Incredibly Close (12A)

Jonathan Safran Foer's second novel, Extremely Loud and Incredibly Close, is a work of mannered chaos where typefaces jostle with photographs, illustrations, blank spaces and inky blocks of blackness. The cacophony reflects the book's setting - New York in the immediate aftermath of 9/11 - as well as the frantic voice of the nine-year-old Oskar Schell, who wanders the bereft city with his tambourine and may or may not have Asperger's syndrome. If the novel's relentless energy gets too much, you can always light some incense sticks, pour a glass of wine, draw a hot bath. No such option is available to viewers of the film unless they can count on an unusually accommodating cinema manager.

After A Cock and Bull Story (Michael Winterbottom's game take on Tristram Shandy) and Time Regained (Raúl Ruiz does Proust), it is hard to argue that any novel is truly unfilmable. But it's evident watching Extremely Loud and Incredibly Close that this movie could never have worked in its current shape. Prone to cuteness the novel may be, but at least it tries to ­interrogate its chosen art form. The film has no such ambition. Its complacent, literal approach magnifies the novel's flaws and introduces some new ones into the bargain.

When Oskar (Thomas Horn) is sent home from school on the morning of September 11 2001, he finds the answerphone blinking in his parents' apartment. A string of messages have been left by his father, Thomas (Tom Hanks), from inside the World Trade Center.

Thomas never makes it back. Some time later, Oskar discovers in his father's closet a mysterious key and embarks on a mission to find the lock that it will open. Flashbacks establish that father and son were enthusiastic adventurers, with Thomas setting challenges for Oskar, such as encouraging him to unearth evidence of New York's vanished sixth borough. As if that weren't enough to make every parent in the audience feel like Frank Gallagher from Shameless, Thomas also reads A Brief History of Time to Oskar in the evenings, rather than What Car? magazine like the rest of us.

It's right that a film seen from Oskar's perspective should show Thomas in an idealised light, but the casting of Hanks, splendid though he is, epitomises Stephen Daldry's approach: why go for a spoonful of sugar when you can have an entire refinery's worth? A less saintly actor (James Gandolfini, say, or Billy Bob Thornton) would have lent ambiguity to the character. Instead, Thomas becomes just another indistinct angel, along with Oskar's mother (Sandra Bullock), who is revealed to be more attentive than she first appears, a mute neighbour (Max von Sydow) and everyone else the child encounters in an incarnation of New York that could pass for Trumpton.

Foer's novel faced similar accusations of excessive whimsy; next to the movie, it is a model of austerity. As he did with Jamie Bell in Billy Elliot, Daldry encourages some alert and vivid acting from a 13-year-old newcomer. But Oskar's ceaseless chatter proceeds very quickly from charming to hectoring, before arriving at the "Please will someone wrap that tambourine around the kid's head?" stage.

The fault lies not with young Horn, who wears a hunted-fawn expression on his soft, angular face, but with how Daldry cuts and shapes his performance. He bombards us with Oskar: there's no respite from his prodigious intelligence. His narration floods the soundtrack, his face is doted on by Chris Menges's camera, his eccentric behaviour (wearing a gas mask on the subway, offering hugs to strangers) is milked for indulgent giggles, and he is given lines that no actor deserves ("Mom, it's OK if you fall in love again").

What renders the movie catastrophic rather than merely mediocre is that it has been made in such bad faith. Any director who could drench a whole film in Alexandre Desplat's sickly, manipulative score must trust his material even less than he trusts his audience. If Daldry were concerned that the story of a boy left fatherless after 9/11 might not be sufficiently poignant, why didn't he saddle Oskar with an orphaned puppy or a terminal disease just to be on the safe side?

Ryan Gilbey is the New Statesman's film critic. He is also the author of It Don't Worry Me (Faber), about 1970s US cinema, and a study of Groundhog Day in the "Modern Classics" series (BFI Publishing). He was named reviewer of the year in the 2007 Press Gazette awards.